I was watching EPI the other day with my wife , the scene were Mace and Yoda discuss if Anakin should be trained.
Mace says he should be, but Yoda finally agrees to let Obi Wan train Anakin - my wife commented that maybe Mace maybe had more wisdom than Yoda, and that Yoda should have forsaw what was going to happen...
A few days later I was watching EP VI ( this isn't regular viewing in my house, I'm just having a refresher this week !) and realised (as Lucas has said) that Anakin's / Vader's actions need to be viewied over the course of all 6 episodes and not just the first 3.
Anakin is indeed the one who brings balance back to the force, and it is Anakin who destroys the Emperor, albeit 40 odd years after the Jedi Council first meet him......